Marine vehicle with hydrofoil exhaust



Oct. 12, 1965 c. KIEKHAEFER 3,211,120

MARINE VEHICLE WITH HYDROFOIL EXHAUST Filed July 16, 1964 I INVENTOR. FIG, 4. ELMER CARL KIEKHAEFER (/pa'ru; F 5farzle Attorneys United States Patent Fla., assignor to Fond du Lac, Wis, a corpo- This invention relates generally to a marine vehicle, such as a boat, which is equipped with hydrofoil structure.

Boats so equipped have the advantage of substantially reduced drag, since at higher speeds the boat hull is lifted clear of the water so that only the hydrofoil, propeller and steering mechanism are beneath the surface.

In marine vehicles powered by one or more internal combustion engines, it is desirable to muflle or quiet the sound of exhaust gases being discharged for the engine. In accordance with the present invention, the exhaust sound is muffled by discharging it deep in the water. More particularly, the invention contemplates a hollow hydrofoil structure wherein the exhaust gases are passed therethrough and discharged below the boat hull.

The accompanying drawing illustrates the best mode presently contemplated by the inventor for carrying out the invention.

In the drawing:

FIGURE 1 is a side elevation of a hydrofoil-equipped boat embodying the invention, and with certain parts shown schematically;

FIG. 2 is a section taken on line 22 of FIGURE 1;

FIG. 3 is a rear end elevation of the boat of FIGURE 1, with certain parts shown schematically; and

FIG. 4 is a detail section taken on line 4-4 of FIG. 3.

As shown in the drawing, the concept of the invention may be applied to a boat 1 of any suitable type adapted to ride in and above the water and adapted to be driven by an inboard internal combustion engine 2 secured therein. Engine 2 is connected through suitable drive mechanism 3 to a rearwardly facing propeller 4 disposed beneath the boat hull generally adjacent the stern. Suitable steering means are provided, such as a manually operated rudder 5 disposed rearwardly of propeller 4.

Boat 1 is adapted to be lifted clear of the water during forward motion thereof. For this purpose, at least two hydrofoils are provided, one fore and one aft.

The front hydrofoil unit 6 comprises a pair of hydrofoil supports or struts 7 secured to the respective sidewalls of the boat hull and which extend downwardly in a diverging manner to substantially below the hull. A generally wide V-shaped hydrofoil 8 is secured to and extends between struts 7 beneath the hull. Hydrofoil 8 may be shaped in any suitable manner to provide the desired lifting action for the bow of the boat at running speeds. The center of the hydrofoil is generally disposed along a vertical plane containing the central boat axis.

Rear hydrofoil unit 9 is generally similar to and substantially spaced from forward unit 6 and also comprises downwardly diverging hydrofoil supports or struts 10 secured at their upper ends to the boat hull and joined at their lower ends by a V-shaped transverse hydrofoil 11. Unit 9 is shown as being spaced rearwardly of pro- 3,211,120 Patented Oct. 12, 1965 peller 4- and it cooperates with hydrofoil unit 6 in lifting the hull at running speeds and providing stability therefore.

Engine 2 drives propeller 4 to move boat 1 through the water, and as the speed of the boat increases hydrofoil units 6 and 9 lift the boat hull clear of the water. However, hydrofoils 8 and 11 normally remained submerged under water, as do propeller 4 and rudder 5.

In accordance with the invention, means are provided to discharge the engine exhaust under water. For this purpose, one of the hydrofoil units, such as rear unit 9, is generally hollow and is provided with a continuous passageway 12 extending throughout and terminating at the boat hull. The hull contains an opening 13 communicating with passageway 12. A conduit 14 is secured to the inside of the hull at each opening 13 and extends to an engine exhaust port 15.

As shown, engine 2 contains two exhaust ports 15, each port being connected to a respective adjacent opening in the hull. Exhaust gases will thus pass downwardly through passageways 12 in both struts. Alternately, the engine may have only one exhaust port, which may be connected by a Y-shaped conduit to both openings 13. If desired, only one strut may be utilized for exhaust transmission.

In order to discharge the exhaust gases under water hydrofoil 11 is provided with at least one discharge opening 16 communicating with passageway 12 and which faces rearwardly to direct the gases sternwise into the water. A plurality of openings 16 are shown. Thus, even when the boat hull is lifted from the water, the gases will be discharged into the water and beneath the hull. Since the trailing edge of the hydrofoil 11 forms a low pressure area behind it, the exhaust gas will be assisted in withdrawal from the engine.

In using a hydrofoil-equipped boat in below freezing weather, wherein the ambient temperature: is below 32 F., ice may tend to collect on the hydrofoil struts and other adjacent parts. Since the engine exhaust gases flowing through passageways 12 are quite hot, the hydrofoil units will be raised to substantially above 320 F. This will prevent or eliminate the formation of ice thereon both when the boat is at rest and at running speeds, especially adjacent the water-air interface which the unit extends through.

While the invention is shown as being applied to the rear hydrofoil unit, it could be applied to the front unit or to all units simultaneously.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

In a marine vehicle having a hull:

(a) an internal combustion engine mounted in the stern of said hull and having an exhaust port for discharging exhaust gases therefrom,

(b) underwater means generally beneath the stern of said hull and connected to said engine for propelling said vehicle through the water,

(c) a rudder adjacent said propelling means for steering said hull,

3, 4 (d) fore and aft hydrofoil means spaced from said pro- References Cited by the Examiner pelling means and adapted to lift the hull of said ve- UNITED STATES PATENTS hicle to above the surface of the water at r nning 2 597 048 5/52 Almovist 114 66.5 speeds, with a portion of said hydrofoil means re- 2980047 4/61 Korganofi 6t 2 maining under water, said aft hydrofoil means being 5 2999475 9 /61 Kautz disposed to the rear of said propelling; means and 3:006:3O7 10/61 Johnson r r, 3,077,173 2/63 Lang 11466.5 (e) and means connected to said engine port for di- 3,085,537 4/63 Headrick et a1 114--66.5

recting engine exhaust gases through said aft hydro- 1O FOREIGN PATENTS foil means to discharge through the said underwater portion thereof into the water in a rearwardly direc- 549266 10/56 Italy tion behind said propelling means and rudder. FERGUS S. MIDDLETON, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,211,120 October 12, 1965 Elmer Carl Kiekhaefe'r It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 19, for "for the engine" read from the engine column 2, line 41, for "320 F..." read 32 Fo Signed and sealed this 19th day of July 1966,

iEAL) ttest:

RNEST W. SW'IDER EDWARD J. BRENNER ttesting Officer Commissioner of Patents 

